By simulating blood flow through narrowed coronary arteries, a new microfluidic device is able to assess the effects of anti-clotting drugs on a person-to-person basis. The device, developed by Georgia Tech’s George W. Woodruff School of Mechanical Engineering, will give doctors the means to administer the correct drug and dosage to a patient without performing manual calculations. Findings are based on a study performed by the research team, which focused on two drugs that prevent blood clotting—aspirin and GPllb/llla-inhibitors.

Patients’ blood was tested in a patent-pending microfluidic device with narrow passageways that simulate the coronary arteries. According to the researchers, the “benchtop” diagnostic device could help prevent heart attacks and lower healthcare costs by providing physicians with better guidance on how drugs may affect individual patients.

In this study, aspirin and GPIIb/IIIa inhibitors were added at different doses to blood samples drawn from patients over several days, and then run through the microfluidic device’s four channels that mimic coronary arteries to monitor the effect the drugs had on clotting at high and normal shear rates. GPIIb/IIIa-inhibitors are traditionally given to patients at high risk for heart attack and can be expensive. When arteries are constricted, blood has to squeeze through narrow passages that trigger a mechanical force called shear. High shear rates create a higher risk of blood clot. 

Researchers discovered that lower shear rates found in normal arteries responded well to aspirin, which stopped platelets from clumping with each other, but the drug didn’t fare as well at higher shear rates. Still, after clots formed, they became unstable and broke off the simulated artery wall. They concluded aspirin was effective in preventing heart attacks, but less so in those battling atherosclerosis (a thickening of the artery wall due to the invasion and accumulation of white blood cells). The study also uncovered that patients may be “aspirin-resistant” and thus should take GPlla/lllb-inhibitors, which were effective at preventing blood clots across all shear rates tested.

The statistical method used for the study—Cox-Hazard analysis—was performed by bioengineering graduate student Nathan Hotaling to determine drug safety for patients. According to the Georgia Tech group, the microfluidic device is the first to address this issue using varying shear rates and patient dosing.  However, before the device can go to a clinic or hospital, the study would need to be performed in a larger setting.